No,
you did not imagine it — Friday night was ridiculously hot —
because it was the hottest Sydney night in January since city weather
records began.

Hottest
nights are measured by the lowest temperature reached during the
night.

On
Friday night, the temperature in the city got to its lowest point at
a sweaty 26.4 degrees Celsius at about 11:00pm, the Bureau of
Meteorology [BOM] said.

Then
it just got hotter, climbing to 31C by 1:00am.

"[Friday
night] was actually the warmest January night the city has ever
recorded, and records for the city station go back to 1858 so there's
quite a while of records there," BOM duty forecaster Rebecca
Kamitakahara said.

But
before you complain too much, eastern city-siders, think about your
wilting buddies out at Penrith in the far west.

At
midnight, it was still around 36C in Penrith, and it took until
4:00am for the gauge to get below 30C.

They
also recorded their highest minimum temperature of 28.6C in Penrith

"That's
actually the warmest night the station was recorded since it opened,
but that station was opened in 1995 so records don't go back as far
as [Sydney city]," Ms Kamitakahara said.

Clouds
trapped the heat

Ms
Kamitakahara said there were two reasons the city did not cool off on
Friday night.

"We
had a combination of an extremely low air-mass over NSW broadly,
which is what is contributing to those heat wave conditions, so there
was a limit to how much it would cool off anyway overnight," she
said.

"In
addition to that we had a fairly decent layer of cloud cover
overnight, which meant the ground couldn't cool off overnight."

Low-intensity
heatwave conditions continue in northern New South Wales and southern
Queensland over the weekend.

The
severity will increase over the coming days and spread back down
across much of the south-east of Australia from Monday to Wednesday,
according to BOM forecasting.